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Fuel Mix Disclosure 

SEMO, as the Fuel Mix Disclosure calculating body, will be implementing the Enduring Fuel Mix Methodology for the disclosure year 2011 and onwards. This methodology will replace the Interim arrangements and is outlined in the decision paper Decision Paper SEM/11/095.

A Market Operator Special Topic (MOST) meeting was held in Dublin on the 29th of February 2011 outlining this methodology. An updated version of the presentation from this meeting outlining the methodology is available here.

Generators who are not covered by a PSO (Public Service Obligation) related PPA (Power Purchase Agreement) and not in receipt of Guarantees of Origin in Ireland or REGOs in Northern Ireland may apply to have the attributes of their generation transferred to a Supplier of their choosing. To do so Generators must register with SEMO and nominate a Supplier. This can be done on a once off basis between a nominated start and end date of production or on an ongoing basis. The form for this process is located

Suppliers, in both Ireland and Northern Ireland, are required to make declarations of Generation they wish to claim annually. These cover Guarantees of Origin (including imports), PSO PPA contracts and Generator Attributes. These submissions are to be made by 31st of March each year for the Disclosure Period of the previous calendar year. If Suppliers do not make a submission by this date, the residual mix will be applied to their Demand.

To find out more about Fuel Mix Disclosure please contact the GO team at or call the Market Helpdesk (please refer to our contact us.

SEMO is a joint venture between EirGrid PLC and SONI Limited